A Daikin air purifier that seems dead or useless often comes down to something ordinary: a loose panel, a dirty filter, bad placement, or a sensor that needs wiping down. Several common symptoms have simple owner checks, including panel seating, filter condition, placement, and sensor cleanliness. Daikin's own troubleshooting guide sorts these complaints into a handful of categories, including units that won't operate, won't discharge air, won't purify, and won't humidify, plus a separate...